On a very basic level if I have a 6 sided box that simulates a room with 2 windows and have a rectangular light inside the box and the skylight and sun turned on outside is there any way to give the ceiling a material that allows the skylight to come through as if it wasn’t there? Is that what Opacity controls in the Physically Based Materials? Does the ceiling look like a ceiling from the inside of the box but allow the sun and skylight to come through as if wasn’t there?
No, such light path controls don’t exist yet in Rhino.
Technically, this is called Light Portal, It used to be utilized a lot in renderers like V-ray as a method of concentrating light rays of the outdoor sun / sky into the portal rectangle, this used to save memory, increase render speed and reduce noise (speckle). This has become more obsolete in the last 10 years due to faster machines and the user’s need for a more user-friendly workflow.
I’d suggest of cutting a hole in your box to simulate skylight.
just hang an extra panel of light (rectangular) into the room, that will be faster to render either, skylight makes renderings rather slow in my experience and dont add much, specifically when you are trying to brighten up the room through the windows, that will just lead to stupid long rendering times.
So if I have a ceiling with a Physically Based Material whose Opacity is dialed down to 0 is that the same as “transparent”? Are you just making that geometry transparent like glass? Is there no way to have a ceiling look like a normal ceiling would from below (opague) but allow the skylight to come through from above so you get ambient room lighting? This is all for the benefit of the camera being below the ceiling looking in to the room, of course. I’m sorry if I’m mixing up my terms.
no, you will want to light the scene as you would for real with the same lights that would be in a scene,
no way to make a transparent ceiling with a opaque bottom.
Thank you!